Sodium alkyl naphthalene sulfonates (SANS) are anionic surfactants. They have one or more short alkyl chains (typically butyl or isopropyl) on a naphthalene ring that carries a sulfonate group. The best-known grade is sodium dibutyl naphthalene sulfonate, often sold as “wetting agent BX” or under the old trade name Nekal. Unlike naphthalene sulfonate formaldehyde condensates (NNO, SNF), SANS are small molecules. Their main job is fast wetting and penetration, not long-term dispersion.
How SANS work as a wetting agent
- The alkyl-naphthalene part adsorbs on low-polarity surfaces such as fibres, hydrophobic powders and pigments. The sulfonate stays in the water.
- Adsorption lowers the interfacial tension and displaces trapped air, so water penetrates powders and fabrics faster.
- Wetting gets a powder or fibre into the water. Keeping particles apart afterwards usually needs a polymeric dispersant (NNO, MF, lignosulfonate).
Where SANS are used
| Application | Role | What to test |
|---|---|---|
| Wettable powders and water-dispersible granules | Wetting agent alongside a dispersant | Wettability (CIPAC MT 53.3), suspensibility, foam |
| Textile pretreatment and dyeing | Penetrant in scouring, bleaching and dye baths | Sinking or wetting time on the actual fabric, foam, bath stability |
| Pigment and filler wet-out | Speeds powder incorporation | Grind time, viscosity, flocculation |
| Rubber latex and emulsion polymerisation | Co-surfactant | Coagulum, particle size, foam |
SANS vs related naphthalene products
| Product | Structure | Main function |
|---|---|---|
| SANS / dibutyl naphthalene sulfonate (BX) | Small alkylated monomer | Wetting, penetration |
| Dispersant NNO | Naphthalene sulfonate formaldehyde condensate | Dispersion of dyes and pigments |
| Dispersant MF | Methylnaphthalene sulfonate formaldehyde condensate | Dispersion with high heat stability for disperse and vat dyes |
| SNF superplasticizer | Naphthalene sulfonate formaldehyde condensate, concrete grade | Cement water reduction |
A similar chemical name does not make these interchangeable. A wetting agent will not act as a concrete superplasticizer, and a condensate dispersant is a poor fast wetter.
Buying and qualification
- Confirm the exact alkyl type, active matter and inorganic salt content from the current TDS and SDS.
- Compare grades by wetting time at equal active concentration, in your own water and temperature.
- Check foam; SANS can foam strongly in agitated baths.
Wetting agents for agrochemical, textile and pigment formulation are handled by the group’s surface chemistry division: sodium dibutyl naphthalene sulfonate uses (greenagrochem.net). For industrial dispersants, see Dispersant NNO and Dispersant MF, or contact info@greenagrochem.com.
Our SANS Grades
| Parameter | SANS powder (GAC-SANS-P) | SANS liquid (GAC-SANS-L) |
|---|---|---|
| Appearance | Cream to pale yellow powder | Yellow-brown liquid |
| Active content | 60–90% | Per batch COA |
| pH (1% solution) | 7.0–8.0 | 7.0–8.0 |
| Sulfate content | 15–30% | 15–30% |
| Other | Moisture ≤ 7.0%; bulk density 0.50–0.70 g/mL | Viscosity 200–1,000 mPa·s; density 1.10–1.30 kg/L |
| Packing | 25 kg PP bags; 500 kg bags | 180/200 kg drums or IBC |
| Shelf life | 12 months | 12 months |
The powder is described in its TDS as thermally stable up to 200 °C. Besides wetting, the TDS list uses as a concrete admixture (workability and air entrainment), ceramic processing aid, dust suppressant, textile levelling agent and detergent surfactant. See the SANS powder product page.
Sodium Alkyl Sulfonate vs Alkyl Naphthalene Sulfonate
“Sodium alkyl sulfonate” usually means an alkane sulfonate (a straight carbon chain with a sulfonate group), used in detergents. Sodium alkyl naphthalene sulfonate has the sulfonate on a naphthalene ring with short alkyl groups, which gives it faster wetting on powders and fibres. Check the CAS number on the SDS to be sure which one a supplier is offering.
Frequently Asked Questions
What is sodium alkyl naphthalene sulfonate used for?
As a wetting agent in wettable powders, textile processing and pigment wet-out, and, according to our TDS, also in concrete admixtures, ceramics, dust suppression, detergents and drilling fluids.
What is the active content of SANS powder?
Our GAC-SANS-P powder has 60–90% active content and 15–30% sulfate, pH 7–8 in 1% solution.
Is SANS the same as dispersant NNO?
No. SANS is a small alkylated molecule for fast wetting; NNO is a formaldehyde condensate polymer used to keep particles dispersed.
